Increasingly, computing systems are being configured as multi-nodal structures wherein individual nodes each include a microprocessor for operating upon a subset of an overall data processing action. Interconnection of such nodes is preferably configured in the form of hard-wired backplanes. Such backplane networks provide highly reliable interconnectivity and maintain interconnection costs at a minimum. However, when all nodal intercommunication wiring is of fixed form, the nodal structure becomes fixed, making system changes difficult and expensive to implement. At the other extreme, nodes may be interconnected by pluggable cabling which renders nodal system changes easily implemented, but significantly raises the cost of nodal interconnections.
It is vital that a multi-nodal system retain an ability to accommodate a change to its nodal configuration without requiring substantial modifications to supporting system components. For instance, a customer may purchase a multi-nodal system exhibiting a first configuration, and over a period of time require additions to the nodal configuration to accommodate added data processing requirements. Such additional nodes should be able to be added to the multi-nodal system while the system is in operation and without requiring significant structural change to the system. The prior art is replete with various interconnection networks for computing systems. U.S. Pat. No. 5,122,691 to Balakrishnan describes an interconnection architecture for a backplane in a computer system. The backplane provides a physical interconnection between a plurality of pluggable modules. Each backplane includes an interconnect chip which provides point-to-point links between the modules and the interconnection topology on the backplane. U.S. Pat. No. 5,243,704 to Baty et al. describes an interconnect system for a multi-nodal system wherein individual nodes are connected to one another over a plurality of bus lines that provide independent communication pathways. The buses are configured in a sparse array so that every node can communicate directly with every other node over a dedicated independent connection pathway and so that no one bus connects together all of the nodes. U.S. Pat. No. 4,967,344 to Scavezze et al. describes a multi-nodal system which is constructed to allow individual node cards to be plugged into a backplane (see FIG. 16). Special purpose cable circuit cards are also pluggable into the backplane and enable non-backplane cable interconnections to be made to other node/backplane assemblies.
U.S. Pat. No. 5,207,583 to DeBalko et al. describes a network interface unit wherein a plurality of circuit cards each include a male and female connector. Each circuit card is inserted into a housing so that the female connectors plug into a motherboard. The male connectors enable external wired connections to be made to the circuit cards.
U.S. Pat. No. 4,971,563 to Wells, III discloses a modular backplane assembly that comprises at least two interchangeable modular backplanes that allow at least two different predetermined types of electrical interconnection hardware and mechanical mountings. U.S. Pat. No. 4,975,695 to Almond et al. discloses a communication node for connection of multiple network processors and multiple packet processors. Each switch matrix has multiple I/O ports with bidirectional data links. The switch matrices are connected to each other by a backplane bus or via bidirectional data links.
U.S. Pat. Nos. 5,203,004 and 5,293,636 to Bunton et al. each disclose a multi-board computer system wherein each set of boards has an associated plug-in connector that enables a separate power supply for each set of boards.
U.S. Pat. No. 5,280,607 to Bruck et al. discloses the addition of spare components (nodes) and extra links to a given target mesh for a fault-tolerant n-dimensional mesh architecture. When a faulty node is detected, the mesh is reconfigured without use of switches.
It is an object of this invention to provide an improved interconnection network for a multi-nodal computing system.
It is another object of this invention to provide an improved interconnection network for a multi-nodal system wherein nodes may be added or removed while the remainder of the nodes remain operational.
It is a further object of this invention to provide an interconnection network where at least a portion of a backplane can be removed without requiring the system be rendered nonoperational.